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  <title>Gets the current key</title>

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 <div class="refnamediv">
  <h1 class="refname">AppendIterator::key</h1>
  <p class="verinfo">(PHP 5 &gt;= 5.1.0)</p><p class="refpurpose"><span class="refname">AppendIterator::key</span> &mdash; <span class="dc-title">Gets the current key</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-appenditerator.key-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="modifier">public</span> <span class="type"><span class="type scalar">scalar</span></span> <span class="methodname"><strong>AppendIterator::key</strong></span>
    ( <span class="methodparam">void</span>
   )</div>

  <p class="para rdfs-comment">
   Get the current key.
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-appenditerator.key-parameters">
  <h3 class="title">参数</h3>
  <p class="para">此函数没有参数。</p>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-appenditerator.key-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   The current key if it is valid or <strong><code>NULL</code></strong> otherwise.
  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-appenditerator.key-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="appenditerator.key.examples.basic">
    <p><strong>Example #1 <span class="methodname"><strong>AppendIterator::key()</strong></span> basic example</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$array_a&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">ArrayIterator</span><span style="color: #007700">(array(</span><span style="color: #DD0000">'a'&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #DD0000">'aardwolf'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'b'&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #DD0000">'bear'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'c'&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #DD0000">'capybara'</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">$array_b&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">ArrayIterator</span><span style="color: #007700">(array(</span><span style="color: #DD0000">'apple'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'orange'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'lemon'</span><span style="color: #007700">));<br /><br /></span><span style="color: #0000BB">$iterator&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">AppendIterator</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">append</span><span style="color: #007700">(</span><span style="color: #0000BB">$array_a</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">append</span><span style="color: #007700">(</span><span style="color: #0000BB">$array_b</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">//&nbsp;Manual&nbsp;iteration<br /></span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">rewind</span><span style="color: #007700">();<br />while&nbsp;(</span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">valid</span><span style="color: #007700">())&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">key</span><span style="color: #007700">()&nbsp;.&nbsp;</span><span style="color: #DD0000">'&nbsp;'&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">current</span><span style="color: #007700">()&nbsp;.&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">next</span><span style="color: #007700">();<br />}<br /><br />echo&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">//&nbsp;With&nbsp;foreach<br /></span><span style="color: #007700">foreach&nbsp;(</span><span style="color: #0000BB">$iterator&nbsp;</span><span style="color: #007700">as&nbsp;</span><span style="color: #0000BB">$key&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #0000BB">$current</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #0000BB">$key&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #DD0000">'&nbsp;'&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #0000BB">$current&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>以上例程会输出：</p></div>
    <div class="example-contents screen">
<div class="cdata"><pre>
a aardwolf
b bear
c capybara
0 apple
1 orange
2 lemon

a aardwolf
b bear
c capybara
0 apple
1 orange
2 lemon
</pre></div>
    </div>
   </div>
  </p>
 </div>


 <div class="refsect1 seealso" id="refsect1-appenditerator.key-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="methodname"><a href="iterator.key.html" class="methodname" rel="rdfs-seeAlso">Iterator::key()</a> - 返回当前元素的键</span></li>
    <li class="member"><span class="methodname"><a href="appenditerator.current.html" class="methodname" rel="rdfs-seeAlso">AppendIterator::current()</a> - Gets the current value</span></li>
    <li class="member"><span class="methodname"><a href="appenditerator.valid.html" class="methodname" rel="rdfs-seeAlso">AppendIterator::valid()</a> - Checks validity of the current element</span></li>
    <li class="member"><span class="methodname"><a href="appenditerator.next.html" class="methodname" rel="rdfs-seeAlso">AppendIterator::next()</a> - Moves to the next element</span></li>
    <li class="member"><span class="methodname"><a href="appenditerator.rewind.html" class="methodname" rel="rdfs-seeAlso">AppendIterator::rewind()</a> - Rewinds the Iterator</span></li>
   </ul>
  </p>
 </div>


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